Concrete mixer



March 16, 1943. H. E. SMITH CONCRETE MIXER Filed April 18, 1941 2 Sheets-Sheet l E mum ATTORNEY March 16, 1943. H. E. SMITH CONCRETE MIXER Filed April 18, 1941 2 Sheds-Sheet 2 INVENTOR flwwwz? 607/719. BY U ATTORNEY.

Patented Mar. 16, 1943 CONCRETE MIXER Harold E. Smith,

Milwaukee, Wis., asslgnor to TheT. L. Smith Company, Milwaukee, Wis., a

corporation of Wisconsin Application April 18, 1941, Serial No. 389,145

6 Claims.

This invention relates to an improvement in concrete mixers of the general type disclosed in United States Letters Patent 2,029,126, granted to A. W. Rybeck, for Mixing apparatus.

In concrete mixers of this type, the materials are mixed in an inclined mixing drum supported for rotation about its longitudinal axis. The drum has one end closed and has its body portion tapering in a conical fashion to its upper high end. The upper high end of the drum is provided with separate openings, one for charging and the other for discharging the drum. A feed chute is pivotally supported adjacent the high end of the drum and may be swung into cooperative relation with the charging opening of the drum or swung away therefrom to provide for discharging of the mixed material. 'Spiral mixing blades are provided within the drum to maintain the material in its state of agitation and also to aid in maintaining the material within the drum. The inclination of the drum, its formation, and the action of the blades prevent discharge of the material from the drum during its rotation in the mixing direction even though no closure be provided for the openings at the discharge end of the drum. However, the feed chute has combined therewith a closing door of laminated ring-like structure, which seals the space between the feed chute and the drum opening, and to some extent participates in the centering and supporting of the feed chute when it is in operative position. When the material is to be discharged the feed chute and closing door are swung up to inoperative position and the direction of rotation of the drum is reversed.

The present invention is concerned with the charging and discharging of materials into and from the drum and aims to accomplish its objects by so constituting the drum and the mixing blades at the high end thereof and so constituting and combining the feed chute and its sealing door therewith that/maximum use is made of the area available for these two operations. The net result is that the charging and discharging operations are carried much more rapidly and effectively than is possible with any of the previously known constructions. And these advantages are accomplished with a construction that is simple, practical, and rugged, easy and comparatively inexpensive to manufacture, and one that is eflicient and highly satisfactory in use.

In carrying out the present invention the drum of a concrete mixer of this character is provided mentary feed opening in open communication with said feed channels and also in open and unobstructed communication with the common charging and. discharging opening at the high end of the drum. As a result material fed to the drum enters directly and simultaneously through both the feed channels and the supplementary feed opening, thereby making the charging operation more rapid and more efiective and more convenient. Of course, during the charging the drum is rotated in the mixing direction. Similarly when the direction of rotation of the drum is reversed, the material is discharged through the channels, and if the load in the drum fills it above the top of the flanges of the blades, the material may flow out through both channels and supplementaryieed opening.

Combined with this basic structure is a feed chute and sealing door of special design in that .the teed chute is dimensioned and proportioned to directly and'simultaneously supply the material flowing therethrough into both the spiral feed channels and the supplementary feed opening. The sealing door is constituted in much the same manner as a conventional one except that rings composing it, while of greater diameter, are of narrower widthto adapt them to coact with the feed chute of enlarged dimension; And in the present construction, the sealing door performs an additional function in that it supplements the action of the feed chute in' constraining the materials being supplied, during the charging of the drum, to flow directly and simultaneously into the spiral feed channels as well as'into the supplementary feed opening.

The supplementary feed opening also provides a sight opening through which the concrete can be directly observed as it is being mixed. When so used, the drum is rotated in a mixing direction, and the combined feed chute and sealing door are swung to inoperative position and out of the way of the sight opening.

Other objects and advantages reside in certain novel features of the construction, arrangement, and combination of parts, which will be hereinafter more fully described and particularly pointed out in the appended claims, reference being had to the accompanying drawings forming a part of this specification, and in which:

Figure l is a fragmentary view partly in vertical, longitudinal cross section and partly in side elevation, illustrating the invention as embodied in the charging end of the mixing drum of a concrete mixer, the feed chute being illustrated in inoperative position, and the apparatus being shown as discharging material from the drum;

Figure 2 is a view taken in the plane of line 2-2 of Figure 1 further illustrating the discharging operation;

Figure 3 is a view similar to Figure 2 showing how the apparatus operates when charging;

Figure 4 is a view similar to Figure 1 but I showing the feed chute in operative position and feeding the material to the drum.

Figure 5 is a fragmentary view in end elevation showing the feed chute elevated to inoperative position and illustrating diametrically a distributing chute arrangement which may be employed;

Figure 6 is a perspective view with parts broken away and shown in section and illustrating the general type of structure but showing three rather than two spiral blades in the mixing drum.

Referring to the drawings, the numeral l0 designates the mixing drum. This drum, which is clearly illustrated in Figure 6, is of the type which is supported for and rotated about an axis inclined about the horizontal. It has one end ll closed and has a conical section 12 which slopes or tapers up to the high end of the drum. The manner in which this drum is mounted and rotated may be varied, and one construction which may be employed is illustrated in the United States patent above referred to.

The present invention proposes to provide at the small end and high end of the drum a common charging and discharging opening designated generally at l3. This opening is formed in'the drum 6. The margin of the opening is surrounded by an annular flange M of angular cross section, which is suitably secured to the metal wall of. the drum.

A plurality of substantially parallel spiral blades ii are fixed to the inner wall of the drum thereof constitutes the major mixing space within the drum. The convolutions of the blades I5 at the high end of the drum are dimensioned. proportioned and fashioned to merge into the margin of the common charging and discharging opening l3. These blades l5 may be of T-shaped cross-section although other cross sections may also be employed. Where they are T-shaped cross sections the'webs of the blades have their outer edges fastened to 'the inner. wall of the drum, and the flanges of the blades constitute the inner peripheries thereof. In order to merge the T-shaped ,blades into the margin of the charging and discharging opening, the flanges are terminated, as at l8, adjacent the opening,

and an unflanged portion I! of the web continues in merging relationship with the margin the axial space I! are in free and unobstructed communication with the common char ing and discharging opening I: so that when the drum is rotated in a mixing direction, the materials to be mixed may be fed directly into both the channel l6 and the axial space 11. When the drum is rotated in a reverse direction, the materials are discharged from the drum. The charging action is illustrated in Figures 3 and 4 and the discharging action in Figures 1 and 2.

The machine is equipped with a feed chute, designated generallyat 20, which has a sloping wall 2| so dimensioned as to insure the flow of the material directly into the spiral channels as well' as into the axial space H. In order to accomplish this the chute 2| is made larger than is customary in this art. Combined with the chute is a sealing or drum-closing door, designated generally at 22, and consisting of a metal ring or annulus 23 contacting the flange i! and rotating therewith. The inner periphery of the ring 23 is rotatively fitted in between the guide rings 24, which are fastened to the feed chute and define a guide groove in which the ring 23 rotates. This sealing door follows the usual pattern of such constructions in the art save that it is appropriately dimensioned to adapt it for use with the feed chute which directly feeds material into the spiral channels l5 as well as into the axial space I! in the mixing drum.

The feed chute is supported as usual for shifting movement into and out of operative position. For this purpose brackets 30 are suitably fastened to the chute and are controlled by a rotatable shaft 3| supported in bearings 32 provided therefor on the upper end of a suitable frame 35. The frame 35 also carries the usual distributing chute structure, designated at 36, and illustrated only diagrammatically in Figure 5.

With the construction a thus described, the charging and discharging are both very substantially facilitated. It will be apparent from Figures 3 and 4 that material flows from the feed chute into both the feed channels l6 and the axial space H. Much more material in very much less time may thus be supplied to the drum than in the devices heretofore lmown in the art wherein material is charged only into an area corresponding to that of the outer or upper end of the axial space H. As pointed out, the outer upper end of the axial space I! in the construction embodying the present invention provides a feed opening which supplements the action of the feed channels I i when charging the drum. This follows from the features of the construction pointed out, and from the fact that the axial space I! not only freely communicates with the feed channels but both the space I1 and the feed channels l6 have unobstructed and open communication with the common feeding and discharging opening it. Similar advantages obtain when discharging.

While I have shown and described one construction in which the invention may be advantageously embodied, it is to be understood that the construction shown has been selected merely for the purpose of illustration or example, and that various changes in the size, shape, and arrangement of the parts may be made without departing from the spirit of the invention or the scope of the subjoined claims.

I claim:

1. A concrete mixer of the character described comprisingarotarymixingdrumhavingomend closedandhavingacommoncharginganddischarging opening at its opposite end, a plurality of flanged combined mixing, feeding, and discharging blades carried by and spiraling around the inner peripheral wall of the drum, the flanges of said blades being cut away adjacent to but inwardly of said opening and the webs thereof merging into the margin of the opening whereby the blades coact wi h the opening to define feed channels and a supplementary axial feed opening in open communication with each other and in unobstructed communication with said common charging and discharging opening, and means for feeding material directly and simultaneously into said feed channels and said supplementary axial feed opening.

2. A concrete mixer of the character described comprising a rotary mixing drum having one end closed and having a common charging and discharging opening at its opposite end, a plurality of substantially parallel spiral blades of T shape in cross section for the major portion of their length, said blades being fixed to the inner wall of the drum and defining spiral feed channels, the convolutions of the blades adjacent said opening having their flanges cut away and having their webs merging into the margin of said opening at angularly spaced points.

3. A concrete mixer of the character described comprising a rotary mixing drum having one end closed and having a common charging and discharging opening at its opposite end and a plurality of substantially parallel spiral blades fixed to the inner wall of the drum and defining open spiral feed channels between the confronting faces of their convolutions, and also defining within the confines of the inner periphery of their convolutions the major mixing space within the drum and supplementary axial feed passage opening thereinto, said feed channels and said supplementary feed passage being in open communication with each other and both having unobstructed communication with said common charging and discharging opening, a feed chute supported adjacent said common charging and discharging opening so as to be movable into and out of cooperative relation therewith, said feed chute when in cooperative relation with said drum opening extending across the open ends of the axial feed passage and the spiral feed channels to feed material supplied thereto directly and simultaneously into the feed channels and into the feed passage, and a ring-like sealing member combined with the feed chute to complete the closure of said common charging and discharging opening and to assist in constraining the material flowing from said chute to feed directly and simultaneously into the spiral feed channels as well as into the supplementary axial feed passage.

4. A concrete mixer of the character described comprising a. rotary mixing drum having one end closed and having a common charging and discharging opening at its opposite end, and a plurality of combined mixing, feeding and discharging blades carried by and spiraling around the inner peripheral wall of the drum to define open spiral feed channels and a supplementary axial feed passage, said axial feed passage being circumscribed by and in open communication with said spiral feed channels, said feed channels and said axial feed passage extending to and terminating in open and unobstructed communication with said common charging and discharging opening, a feed chute having a discharge passage of greater transverse dimension than the transverse dimension of said axial feed passage at said drum opening and means for movably mounting said feed chute at said opening with said discharge end of the chute overlying and unobstructedly communicating with the open ends of said axial feed passage and said spiral feed channels whereby material flowing from said chute may be charged simultaneously and directly into the spiral feed channels and the axial feed passage.

charging opening at its opposite end, and a plurality of combined mixing, feeding and discharging blades carried by and spiraling around the r inner peripheral wall of the drum to define open spiral feedchannels and a supplementary axial feed passage, said axial feed passage being circumscribed by and in open communication with said spiral feed channels, said feed channels and said axial feed passage extending to and terminating in open communication with said common charging and discharging opening, a feed chute having a discharge passage of greater transverse dimension than the transverse dimension of said axial feed passage at said drum opening, said common charging and discharging opening of the drum and the discharging passage of the chute being entirely unobstructed save for the portions of the blades which define said feed channels, and means for movably mounting said feed chute at said opening with said discharge end of the chute overlying and communicating with the open ends of said axial feed passage and said spiral feed channels whereby material flowing from said chute may be charged simultane-- ously and directly into the spiral feed channels and the axial feed passage;

6. A concrete mixer of the character described comprising a rotary mixing drum having one end closed and having a common charging and discharging opening at its opposite end, and a plurality of combined mixing, feeding, and discharging blades carried by and spiraling around the inner peripheral wall of the drum, said blades merging into the margin of the opening whereby the blades coaot with the opening to define spiral feed channels and a supplementary axial feed opening, said feed channels and said supplementary axial feed opening being in open communication with each other at and in unobstructed communication with said common charging and discharging opening, a charging chute, and

means for positioning said chute with the dis-' HAROLD E. SMITH. 

